It is common practice in the automotive art to include in the vehicle's instrument panel, typically to the left of the steering wheel, a headlight switch (with a buzzer circuit) for turning the parking and headlights "on" and "off" by means of a longitudinal pulling or pushing action, respectively, which switch is also combined with a rheostat for dimming or brightening the panel lights on the dashboard by a circular, twisting or rotary motion, to a final clockwise position completely turning them off.
Likewise, this switching structure more recently has been used as well to turn another light "on" and "off," such as, for example, the interior dome light. The function of the dome light switch is to, for example, turn off the dome light circuit, when one or more of the vehicle's doors or tailgate is open during day light hours, by rotating the shaft of the overall switch to the extreme clockwise position (as viewed from the front).
It has been the further practice to have the basic composite switch integrated in its design and occupy a relatively limited and particularly sized space with standardized mounting brackets located in particular locations, so that the composite switch can be mounted in a number of different cars within a car maker's line(s).
In the prior art design, particularly for example in the "Chrysler" switch for this purpose, the supplemental "on"/"off" switch for the dome light was mounted on the side, exterior of the otherwise in-line construction, with the prior art switch having an exposed arm extending generally longitudinally and parallel to the center axis of the switch with its front end bent inwardly to position its distal tip adjacent to the side of the rheostat, so that a projection on the rheostat would cause the switch arm to be moved, breaking the normal electrical contact within the switch.
Such a design added to the bulk of the main switch body and caused significant alignment problems. Additionally, by extending off of the side of the main body of the switch, the dome light switch became more vulnerable to damage in the handling and assembling of the basic switch body into the vehicle. Sometimes the exposed switch arm became bent or misaligned, failing to thereafter engage the rheostat, causing the switching function to no longer be operative.
It additionally had excessive tolerance stack-ups on component parts. Also, the switch arm required ultrasonic welding between it and its associated terminal, a relatively difficult process.
For further background information on an alternate resolution to this problem, reference is had to assignee's co-pending U.S. patent application Ser. No. 07/116,085 of William M. Riser et al filed Nov. 3, 1987, entitled "Combined, In-Line Spacer and Switch, Particularly for A Vehicle's Light," issued as U.S. Pat. No. 4,827,241 on May 2, 1989, the disclosure of which is incorporated herein by reference.
Additionally, recently it has also become desirable to have the rotary action of the same switch control a supplemental fluorescent light circuit for brightening the panel in day light situations. This additional function further adds to the possibility of greater bulk to the switch.